A technical problem to be solved for such an active-antenna radar is that of providing it with passive RESM listening means that operate in the emission band of the radar without increasing the volume occupied by its electronics and, in particular, while using the same receiver to simultaneously or sequentially provide the electronic support measures (ESM) and radar functions.
The same problem may arise in the field of communication emitters and receivers performing a communications electronic support measures (CESM) function.
Currently, RESM and radar equipment are separate. It is sometimes possible to share the same antennae to perform two functions but this is possible only with:
different receiving means;
or sharing of time between the two functions, this causing a loss in performance in each of the radar or ESM functions, in particular as regards the probability of interception.
In these two cases, the overall cost is high and integration of the two pieces of radar and ESM equipment may be difficult, in particular for an on-drone or on-helicopter airborne application.
Moreover, the RESM receiver cannot listen while the radar is emitting, because it would be saturated by this emission.